In her new book on American Muslims, Mecca and Main Street, Geneive Abdo argues that in the post-9/11 world, young American Muslims in particular are taking a "rejectionist" stance. Do you agree with her assessment?

I have no doubt her reporting has 100 percent integrity, that everyone she's interviewed has said just what she's written. Some of the scenes that she paints are very compelling and poignant, and I have people saying similar things in my book at times. A first step toward making sense of the discrepancy between her book and my book is the old cliché, "Is the glass half full or half empty?" You can look at an ambiguous situation and describe it in more hopeful terms, citing, for example, historical experiences or other elements of context that may undercut the narrative of alienation you hear.

If you ask young people on college campuses about their concerns for the world, you'll hear some pretty passionate, heartfelt, extreme - by which I don't mean extremist - and emotional descriptions of the way things are. That's a trope for people who are 20 years old. My thought is: Check back with that person when they're halfway through medical school, or after they've married or had kids. Have a little patience.

My experience is no more scientific than Genny Abdo's - we both went out and talked to a lot of people - but it showed me that while there is a certain degree of pessimism among many (young American Muslims), that pessimism is not fatal or necessarily permanent. And barring further calamitous events - knock wood, God-willing, whatever you like to say - that we don't have anything like 9/11 again, a very impressive success story that has been underway for decades will get back on track.

Immigrants who come to a new society are, by definition, displaced, and there's a certain longing for the old country. Their children have lived with a foot in the new country and a foot in the old country, and they are searching for identity; this is a very classic American experience. Look at the literature of Catholics who have come to this country. Look at the literature of Jews. By literature, I mean fiction as well as social science, and you will see similar patterns. You're the outsider. People hate you. You wonder what you're doing here. You wonder whether you're being seduced by the material values of this overpowering secular culture, and it causes you to ask painful questions. Now, throw in the most calamitous terrorist incident in American history, and we are shocked that people are somewhat alienated?

I have a lot of respect for Genny Abdo's reporting, and I'll happily say that she knows much more about Islam than I do, certainly all around the globe. We just have different instinctive reactions to the material.

At the policy level there is a lot of talk about encouraging "moderate Islam" here and abroad. How would you define "moderate Islam"?

That's a potentially perilous question to answer, because I don't want to insult anyone. "Moderate Islam" is viewed almost as a pejorative by Muslims - a way for outsiders to sort Muslims out according to their degree of moderation. I want to acknowledge my awareness of that concern on Muslims' part. At the same time, I insist there's nothing illegitimate about discussing whether people are moderate or immoderate. We do it in other aspects of social and political life: we talk about politicians or religious figures in other faiths that way.

Admirable elements of moderation include the ability to empathize with people you passionately disagree with, and seeing there may be lessons to be learned from their views and their experiences. Those lessons may cause one to rethink how you live with people who disagree with you in a culture that is explicitly pluralistic, which is to say a culture that is almost certainly never going to transform itself into one where everyone agrees with you.

Moderates in the political sphere are frequently admired or deplored because of their willingness to compromise. Someone on the far left or far right might say, "That weak-kneed moderate, always willing to sell out on principles." That's one perspective. Another perspective is you need a degree of moderation in politics, a degree of compromise, a willingness to find a position between the two poles people can live with. If compromise weren't necessary, we wouldn't need a legislature; we'd always want the same thing, instinctively. We would be a tribe where we all thought the same way.